Fahey P F, Allen J B
J Acoust Soc Am. 1985 Feb;77(2):599-612. doi: 10.1121/1.391878.
We report here several measures of nonlinear effects in the mammalian ear made in the external auditory meatus and in single neurons of the auditory nerve. We have measured the 2f1-f2 and the f2-f1 distortion products and we have found that the neural distortion product threshold curve for 2f1-f2 mirrors the low-frequency side of the frequency threshold curve, when the neural distortion product threshold curve of 2f1-f2 is plotted versus log(f2/f1) its slope is about 50 dB/oct and its intercept is 10-20 dB above the frequency threshold at the characteristic frequency CF, substantial 2f1-f2 distortion was seen in all animals studied while the f2-f1 distortion product was only rarely found at substantial levels, and the distortion product pressure observed in the ear canal was at a level equal to that detected at threshold by the neural units under study. We have also made measurements of two-tone rate suppression thresholds using two new and consistent threshold paradigms. We find that for high and intermediate characteristic frequency neural units the suppression threshold is independent of frequency and at a level of about 70 dB SPL, the suppression above CF is much less than below CF, and the tip of the frequency tuning curve can be suppressed by up to 40 dB by a low-frequency suppressor.
我们在此报告在哺乳动物耳的外耳道及听神经单个神经元中所测得的几种非线性效应的指标。我们测量了2f1 - f2和f2 - f1畸变产物，发现当2f1 - f2的神经畸变产物阈值曲线相对于log(f2/f1)绘制时，其斜率约为50 dB/倍频程，截距在特征频率CF处比频率阈值高10 - 20 dB，在所有研究的动物中均观察到显著的2f1 - f2畸变，而f2 - f1畸变产物仅偶尔在显著水平被发现，并且耳道中观察到的畸变产物压力与所研究的神经单元在阈值时检测到的水平相当。我们还使用两种新的且一致的阈值范式测量了双音速率抑制阈值。我们发现，对于高和中等特征频率的神经单元，抑制阈值与频率无关，约为70 dB SPL，CF以上的抑制远小于CF以下的抑制，并且频率调谐曲线的峰值可被低频抑制器抑制高达40 dB。
